1. Field of the Invention
The present invention relates to an endoscope and a manufacturing method of an endoscope, and in particular, relates to a small diameter endoscope which promotes downsizing and cost reduction, and for example, is used for surgery, and a manufacturing method of an endoscope.
2. Description of the Related Art
In the related art, an endoscope for capturing an image of an internal body of a patient, and an inner portion of an instrument or a structure has become widespread in a medical field or an industrial field. In an insertion portion of such an endoscope which is inserted into an inner portion of an observation target, light from an image capturing portion forms an image on a light receiving surface of an image sensor by an objective lens system, and the image forming light is converted into an electric signal and transmitted to an external image processing device or the like through a signal cable as a projected image signal. In a hard portion disposed in a leading end of such an endoscope, a plurality of components such as an image capturing element, and an optical element, for example, a lens forming a light image on an image capturing surface of the image capturing element is arranged. Recently, in an endoscope having such a complicated configuration, it is important to more easily manufacture the endoscope and to further decrease an outer diameter for reducing a burden of a person to be treated.
For example, in Japanese Patent. Unexamined Publication No. 3-12124, an electronic endoscope forms a concave portion in a substrate, and includes a solid image capturing element in the concave portion. A conductive line is installed between the solid image capturing element and an upper surface side of a step portion in the substrate. The conductive line portion is sealed with a resin, and a glass plate is adhered to the light receiving surface of the solid image capturing element. A frame is disposed on the substrate by being secured in contact with an outside portion from a connection portion of the conductive line. Then, the frame is secured to a barrel of an objective lens.
In the electronic endoscope having the configuration described above, the glass plate is bonded to the light receiving surface of the solid image capturing element, the frame is secured in contact with the substrate, and the barrel of the objective lens is secured to the frame. Accordingly, a reduction in a diameter of the insertion portion and a reduction in a length of a leading end hard portion in an axis direction are promoted.
In the above-described electronic endoscope of an example of the related art, the frame is secured to the substrate, and the frame is secured to the barrel of the objective lens, and thus a diameter greater than or equal to that of the solid image capturing element is required, and it is difficult to reduce the diameter. In addition, the number of components increases, and thus the cost also increases.